JP2000020974A - Optical disk apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical disk apparatus which permits improvement of the follow-up ability of an optical head main body with respect to the movement of an object lens. SOLUTION: This optical disk device 1 has a rotary drive mechanism with an optical disk loaded 2 and rotates, an optical head 3, an optical head moving mechanism provided with a thread motor 7 for moving an optical head 3 in the direction of the radius, a control means 9 for incorporating a pulse generating circuit 91, a tracking error signal generating circuit 21, a tracking servo circuit 22, a thread servo circuit 23, and a comparator 24. A tracking servo signal is generated from a tracking error signal by a tracking servo circuit 22, a thread servo signal is generated from a tracking servo signal by a tracking servo circuit 22, and they are binarized by the comparator 24. A control means 9 generates and outputs a pulse signal for driving the thread motor 7, when a signal level from the comparator 24 changes from L to H.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an optical disk device.

[0002]

2. Description of the Related Art There is known an optical disk device for reproducing or recording / reproducing a read-only optical disk such as a CD and a CD-ROM, and a recordable / reproducible optical disk such as a CD-R and a CD-RW.

FIG. 5 is a block diagram showing a conventional optical disk device, and FIG. 6 is a timing chart of a thread servo signal (voltage) of the conventional optical disk device.

As shown in FIG. 5, a conventional optical disk drive 210 includes a rotation drive mechanism (not shown) for mounting and rotating an optical disk, and an optical head (optical head) capable of moving in a radial direction with respect to the mounted optical disk. Pickup) 2
30; an optical head moving mechanism including a thread motor 270 and a driver 271 for radially moving the optical head 230; a thread servo circuit 260; a driver 242 for driving a tracking actuator 241 to be described later; Circuit 220
And a tracking servo circuit 250.

The optical head 230 includes an optical head main body (optical pickup base) having a laser diode and a divided photodiode (not shown), and the optical head main body can be moved in the radial direction and the rotation axis direction of the optical disk, respectively. An objective lens (not shown) supported by a suspension spring, a tracking actuator 241 for moving the objective lens in the direction of the rotation axis (the optical axis direction of the lens), and a focus actuator (not shown) for moving the objective lens in the radial direction. It is configured.

In such an optical disk device 210, the optical head 230 is moved onto a predetermined track (target address) on the optical disk, and information (data) is recorded or recorded on this track while performing focus control, tracking control, and the like. Play (read).

For example, at the time of reproduction, the tracking actuator 241 is driven by the tracking control so that the objective lens follows the target track, but the thread motor 270 is driven to cover the limit of the on-track due to the driving of the tracking actuator 241. The optical head body is moved to control the objective lens to return to the neutral position (center).

That is, at the time of reproduction, the tracking error signal generation circuit 220 uses the signal from the optical head 230 to determine the magnitude and direction of the displacement of the objective lens in the radial direction from the track center (from the track center). A tracking error signal (voltage) indicating the amount of deviation is generated. This tracking error signal is input to the tracking servo circuit 250.

The tracking servo circuit 250 generates a tracking servo signal (voltage) for returning the objective lens to the center of the track based on the tracking error signal. The tracking servo signal is input to the tracking actuator 241 via the driver 242 and also to the thread servo circuit 260.

In accordance with the tracking servo signal, a tracking actuator 241 is provided via a driver 242.
Is driven, and the objective lens follows the target track.

In the thread servo circuit 260, a thread servo signal (voltage) is generated based on the tracking servo signal. This sled servo voltage is a voltage corresponding to the amount of deviation from the neutral position of the objective lens (a voltage corresponding to a drive voltage applied to the tracking actuator 241), and is input to the sled motor 270 via the driver 271.

The sled servo signal drives the sled motor 270 via the driver 271, thereby moving the optical head body and returning the objective lens to the neutral position.

In this case, as shown in FIG. 6, the sled servo signal (voltage) is continuously input (applied) to the sled motor 270 via the driver 271. And
The sled motor 270 is stopped until the sled servo voltage reaches a voltage (starting voltage) at which the sled motor 270 operates. When the sled servo voltage reaches the starting voltage, the sled motor 270 operates and the optical head body moves. .
As a result, the objective lens approaches the neutral position, and the sled servo voltage decreases.

However, in the conventional optical disk device 210, the driving amount of the sled motor 270, that is, the moving amount of the optical head main body varies due to fluctuations in the load of the mechanism, and the objective lens does not return to the neutral position. (The optical head body has poor followability).

For example, as shown in FIG. 6, when the load of the mechanism fluctuates, the starting voltage of the sled motor 270 becomes V _1.
To V ₂ and V ₂ to V ₃ , and the objective lens is located at a position far away from the neutral position due to the fluctuation of the starting voltage and the fluctuation of the load of the mechanism (the thread servo voltage becomes zero). Does not converge).

[0016]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an optical disk apparatus capable of improving the followability of an optical head body to the movement of an objective lens.

[0017]

This and other objects are achieved by the present invention which is defined below as (1) to (10).

(1) A rotation drive mechanism for mounting and rotating an optical disk, an objective lens, an optical head main body, and an actuator for moving the objective lens relative to the optical head main body in a radial direction of the optical disk, An optical head provided so as to be movable in a radial direction of the optical disk, and an optical head moving mechanism that includes a thread motor and moves the optical head in the radial direction of the optical disk by driving the thread motor; An optical disc device that performs recording and / or reproduction with respect to the optical disc, and further includes a shift amount detecting unit that detects a shift amount of the objective lens with respect to a reference position set on the optical head main body. When the detected shift amount reaches a threshold, the sled motor is
An optical disc device, wherein a pulse voltage of a predetermined pattern is applied to drive the sled motor.

(2) The optical disk device according to (1), wherein the threshold value is smaller than a movement limit value of the actuator from the reference position.

(3) The optical disk device according to the above (1) or (2), wherein the pulse voltage of the predetermined pattern comprises a first pulse voltage and a second pulse voltage having different polarities.

(4) applying the first pulse voltage;
The optical disc device according to the above (3), wherein the application of the second pulse voltage is performed continuously.

(5) The optical disk device according to (3) or (4), wherein the absolute value of the second pulse voltage is less than the absolute value of the first pulse voltage.

(6) The optical disk device according to any one of (3) to (5), wherein the absolute value of the first pulse voltage is sufficiently larger than the absolute value of the voltage at which the sled motor operates.

(7) The optical disc device according to any one of (1) to (6), wherein the shift amount detecting means detects the shift amount based on a drive voltage of the actuator or a voltage corresponding thereto.

(8) The configuration according to (7), wherein when the drive voltage of the actuator or a voltage corresponding thereto reaches a reference voltage value, the shift amount reaches the threshold value. Optical disk device.

(9) When driving the actuator to cause the objective lens to follow a predetermined track of the optical disk, the optical head main body is moved by driving the sled motor, whereby the objective lens is moved to the reference position. The optical disc device according to any one of the above (1) to (8), which is configured to return to the position.

(10) The optical disk device according to any one of (1) to (9), wherein the thread motor is a DC motor.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an optical disk drive according to the present invention will be described in detail based on a preferred embodiment shown in the accompanying drawings.

FIG. 1 is a block diagram showing an embodiment (main part) of an optical disk apparatus of the present invention, and FIG. 2 is a plan view showing an embodiment (with a casing removed) of the optical disk apparatus of the present invention.

The optical disk device 1 shown in these figures is a CD-ROM drive device for reproducing an optical disk (CD-ROM) 2.

A spiral track is formed on the optical disk 2. The optical disk device 1 has a rotation drive mechanism for mounting and rotating the optical disk 2. The rotation drive mechanism mainly includes a spindle motor 11 for rotating the turntable, and a turntable 13 fixed to the rotation shaft 12 of the spindle motor 11 and on which the optical disc 2 is mounted.
And a driver (not shown) for driving the spindle motor 11.

The optical disk apparatus 1 moves in the radial direction of the optical disk 2 (radial direction of the turntable 13), that is, in the direction of arrow A in FIG. An optical head (optical pickup) 3 to be obtained, an optical head moving mechanism for moving the optical head 3 in the radial direction, a control means 9, a tracking error signal generation circuit 21, a tracking servo circuit 22, and a thread servo circuit 23 And the comparator 24
And a casing (not shown) for accommodating them. Hereinafter, the radial direction of the optical disk 2 is simply referred to as “radial direction”.

The optical head 3 includes an optical head body (optical pickup base) 31 having a laser diode (light source) 5 and a divided photodiode (light receiving section) 6, an objective lens (condensing lens) 32, an actuator 4, It has.

The objective lens 32 is a suspension spring (not shown) provided on the optical head main body 31 (biasing means).
, And can be moved relative to the optical head main body 31 both in the radial direction and in the rotation axis direction of the optical disc 2 (turntable 13) (the optical axis direction of the objective lens 32). The objective lens 32 is at its neutral position (middle point)
Then, the objective lens 32 is urged toward the neutral position by the elastic force (restoring force) of the suspension spring. Hereinafter, the direction of the rotation axis of the optical disc 2 will be simply referred to as “the direction of the rotation axis”.

The actuator 4 includes an optical head body 31
In contrast, the objective lens 32 is moved in the optical axis direction (rotation axis direction).
A focus actuator (not shown) for moving
A tracking actuator 41 for moving the objective lens 32 in the radial direction (inner and outer peripheral sides of the optical disc 2) around a reference position set on the optical head main body 31 is configured.

In the optical disc device 1, various conditions such as the position of the tracking actuator 41 and the position of the suspension spring are set so that the reference position and the neutral position coincide with each other.

Taking the radial movement of the objective lens 32 as an example, when no voltage is applied to the tracking actuator 41, the objective lens 32 is located at the reference position by the elastic force of the suspension spring.

The tracking actuator 41
When a predetermined voltage is applied through the driver 42 via the driver 42, the tracking actuator 41 is driven and the objective lens 32 moves in the radial direction according to the voltage value (positive / negative and magnitude). That is, the objective lens 32 is displaced from the reference position by a predetermined amount in the radial direction (the inner circumference or the outer circumference of the optical disc 2) according to the voltage value (positive / negative and magnitude).

The optical head body 31 is formed with three support portions (sliders) 311 that slide along the guide shaft 16 described later.

The optical head moving mechanism mainly includes a sled motor (feed motor) 7, a driver 71 for driving the sled motor 7, a lead screw (worm gear) 81 fixed to the rotating shaft 8 of the sled motor 7, It comprises a reduction gear 14, a rack gear 15, a pair of guide shafts 16, 16 for guiding the optical head 3, and the three support portions (sliders) 311 described above.

The reduction gear 14 comprises a worm wheel 141 meshing with the lead screw 81, and a pinion gear 142 fixed concentrically to the worm wheel 141 and having a smaller diameter than the worm wheel 141.

The rack gear 15 meshes with the pinion gear 142 and is fixed to the optical head main body 31.

As described above, the optical head 3 supports the pair of guide shafts 16, 16 with the support portions 31.
1 movably supported.

The thread motor 7 is controlled by drive control described later.
When the rotating shaft 8 and the lead screw 81 rotate in a predetermined direction, the worm wheel 141 and the pinion gear 142 rotate in a predetermined direction, and the rack gear 1 rotates.
5 and the pinion gear 142, the pinion gear 1
42 is converted into a linear motion of the optical head 3,
The optical head 3 moves in a predetermined direction along the guide shaft 16.

When the rotation shaft 8 of the thread motor 7 and the lead screw 81 rotate in the opposite direction, the optical head 3 moves along the guide shaft 16 in the opposite direction. As the thread motor 7, a DC motor is preferably used.

The control means 9 is usually constituted by a microcomputer (CPU), and includes the optical head 3 (actuator 4, laser diode 5, etc.), thread motor 7, spindle motor 11, tracking servo circuit 22, thread servo circuit 23, etc. , And controls the entire optical disk device 1.

The control means 9 has a built-in pulse generation circuit (pulse voltage generation means) 91.

The control means 9 and the comparator 24
A shift amount detecting means for detecting a shift amount of the objective lens 32 with respect to a reference position set on the optical head main body 31 is configured.

An external device (for example, a computer) is detachably connected to the optical disk device 1 via an interface control unit (not shown).
And an external device.

Next, the operation of the optical disk device 1 will be described. The optical disk device 1 moves the optical head 3 to a target track (target address), and performs focus control, tracking control, sled control, rotation speed control (rotation speed control), and the like on this target track, while performing optical control from the optical disk 2. Reading (reproduction) of information (data) is performed.

At the time of reproduction, a laser beam 51 is emitted from the laser diode 5 of the optical head 3 onto a predetermined track of the optical disk 2. This laser light is reflected on the recording surface of the optical disk 2, and the reflected light is received by the split photodiode 6 of the optical head 3.

A current corresponding to the amount of received light is output from the divided photodiode 6, and this current is supplied to an I / O (not shown).
-V amplifier (current-voltage conversion unit) is converted to voltage,
Output from the optical head 3.

By adding or amplifying the voltage (detection signal) output from the optical head 3, H
An F (RF) signal is generated. This HF signal is an analog signal corresponding to pits and lands written on the optical disc 2.

This HF signal is binarized and EFM (Ei
ght to Fourteen Modulation), and is decoded (converted) into data (DATA signal) in a predetermined format.

The data is decoded into data of a predetermined format for communication (transmission), and transmitted to an external device (for example, a computer) via an interface control unit (not shown).

The tracking control and the thread control in the reproducing operation as described above are performed as follows.

The signal (voltage) after the current-voltage conversion from the divided photodiode 6 of the optical head 3 is input to the tracking error signal generation circuit 21. The tracking error signal generation circuit 21 generates a tracking error signal (TE) (voltage) based on the signal after the current-voltage conversion from the divided photodiode 6.

The tracking error signal is output from the objective lens 32 in the radial direction of the optical disc 2 from the center of the track.
Is a signal indicating the magnitude and direction of the deviation (the deviation amount from the center of the track).

The tracking error signal (TE) is input to the tracking servo circuit 22.

The tracking servo circuit 22 performs predetermined signal processing such as phase inversion and amplification on the tracking error signal, thereby generating a tracking servo signal (TS) (voltage).

The tracking servo signal is a signal for driving the tracking actuator 41 so that the objective lens 32 moves to the center of the track (so that the level of the tracking error signal becomes 0 level) (driving voltage of the tracking actuator). ).

The level of the tracking servo signal, that is, the voltage value, corresponds to the magnitude of the displacement of the objective lens 32 in the radial direction from the reference position and its direction (the amount of displacement of the objective lens 32 with respect to the reference position). ing.

The tracking servo signal (TS) is input to the tracking actuator 41 via the driver 42 and also to the thread servo circuit 23.

The tracking actuator 41 is driven based on a tracking servo signal.
Moves towards the center of the truck. That is, tracking servo is applied.

The drive of the tracking actuator 41 alone has a limitation in causing the objective lens 32 to follow the track. To cover this, the thread motor 7 is driven to move the optical head main body 31 to the objective lens 32.
Moves in the same direction as the direction in which the object lens 32 has moved, and controls the objective lens 32 to return to the reference position (performs sled control).

The thread servo circuit 23 performs predetermined signal processing such as removal and amplification of high-frequency components on the tracking servo signal input from the tracking servo circuit 22, whereby the thread servo signal (SS) (tracking actuator Voltage corresponding to the drive voltage of
Is generated.

The level of the thread servo signal, that is, the voltage value, depends on the magnitude and direction of the displacement of the objective lens 32 in the radial direction from the reference position (the objective lens 32).
Of the reference position).

The thread servo signal (SS) is input to a comparator (comparator) 24 and is binarized by the comparator 24. This binarized signal (voltage) is output from the comparator 24 and input to the control means 9.

FIG. 3 shows a thread servo signal (voltage), a signal (voltage) from the comparator 24, and a pulse generation circuit 91.
5 is a timing chart of a signal (voltage) from the first embodiment.

As shown in FIGS. 3A and 3B, the level of the signal from the comparator 24 is such that the level (voltage value) of the sled servo signal is a threshold level (reference voltage value).
In the above case, the level becomes high level (H), and when the level (voltage value) of the thread servo signal is lower than the threshold level (reference voltage value), it becomes low level (L).

When the amount of deviation of the objective lens 32 from the reference position reaches the threshold value, the threshold level (reference voltage value) of the comparator 24 and the threshold level (voltage value) of the thread servo signal Value) is set in advance so as to match.

Further, the threshold value is smaller than the movement limit value of the tracking actuator 41 from the reference position.

In this case, the threshold level (reference voltage value) of the comparator 24 is 90% or less of the level (voltage value) of the thread servo signal when the displacement of the objective lens 32 with respect to the reference position is the movement limit value. Preferably 60-7
About 0% is more preferable.

When the threshold level is equal to or less than the upper limit, thread control can be performed more reliably.

In the optical disk device 1, when the level of the signal from the comparator 24 changes from low level (L) to high level (H), the amount of deviation of the objective lens 32 from the reference position has reached the threshold value. It is assumed.

That is, as shown in FIG. 3C, when the level of the signal from the comparator 24 changes from a low level (L) to a high level (H), the control means 9 controls the pulse generation circuit 91. A pulse signal (pulse voltage) of a predetermined pattern is generated and output.

The pattern of the pulse voltage generated by the pulse generation circuit 91 is set in advance so that the objective lens 32 returns to the reference position when the sled motor 7 is driven based on the pulse voltage.

The pulse voltage from the pulse generation circuit 91 is
This is applied to the thread motor 7 via the driver 71.

The sled motor 7 is driven based on the pulse voltage. By driving the sled motor 7, the optical head main body 31 moves in the same direction as the moving direction of the objective lens 32, and the objective lens 32 moves to the reference position. Return. That is,
The optical head body 31 follows the objective lens 4.

As shown in FIG. 3C, the pulse voltage is a first pulse voltage (positive pulse voltage) having a different polarity.
51 and a second pulse voltage (negative pulse voltage) 52.

The absolute value of the first pulse voltage 51 is sufficiently larger than the absolute value of the voltage (starting voltage) at which the sled motor 7 operates when the sled motor 7 is incorporated in the optical disk device 2.

In this case, the absolute value of the first pulse voltage 51 is one of the absolute value of the voltage at which the sled motor 7 operates.
It is preferably at least 20%, more preferably about 150 to 170%.

The absolute value of the second pulse voltage 52 is
It is less than the absolute value of the first pulse voltage 51.

In this case, the absolute value of the second pulse voltage 52 is preferably 90% or less of the absolute value of the first pulse voltage 51, more preferably about 50 to 70%.

In this embodiment, the first pulse voltage 5
Although the pulse width (application time) of 1 is the same as the pulse width (application time) of the second pulse voltage 52, in the present invention,
These may be different.

The first pulse voltage 51 of the pulse voltage
And the second pulse voltage 52 are continuous. Thus, the application of the first pulse voltage 51 and the application of the second pulse voltage 52 to the thread motor 7 are continuously performed in this order.

When the above-mentioned pulse voltage is applied to the sled motor 7 via the driver 71, the sled motor 7 is operated by the first pulse voltage 51, its rotation is accelerated, and the sled motor 7 is rotated by the second pulse voltage 52. The motor 7 is braked (brake is applied), and the sled motor 7 stops so that the objective lens 32 is located at the reference position.

In this case, the absolute value of the first pulse voltage 51 is made sufficiently larger than the absolute value of the voltage at which the sled motor 7 operates, and the sled motor 7 is forcibly stopped by the second pulse voltage 52. Therefore, even if the load of the mechanism fluctuates, the effect can be reduced or prevented, and the effect of hunting or cogging of the sled motor 7 can be effectively prevented.

As a result, the thread control can be stably and reliably performed, and the reproduction can be reliably performed.

Next, the control operation of the control means 9 at the time of thread control will be described. FIG. 4 is a flowchart showing the control operation of the control means 9 at the time of thread control. Hereinafter, description will be made based on this flowchart.

As shown in the figure, it is determined whether or not the level of the signal (voltage) from the comparator 24 has changed from low level (L) to high level (H) (step 10).
1).

When the determination in step 101 is "NO", that is, when the level of the signal from the comparator 24 holds the low level (L) and when the level of the signal from the comparator 24 is the high level ( H) and the level of the signal from the comparator 24 is high (H).
, The pulse signal (pulse voltage) is not output (step 10).
2) Return to step 101 and execute step 101 and subsequent steps again.

Also, the judgment in step 101 is "Y
In the case of "ES", that is, when the level of the signal from the comparator 24 changes from low level (L) to high level (H), the pulse signal (pulse voltage) is generated by the pulse generation circuit 91 as described above. And outputs the pulse signal from a microcomputer DA terminal (not shown) (step 1).
03).

After step 103, step 101
And execute the steps 101 and subsequent steps again.

As described above, according to the optical disk device 1, even if the load of the mechanism fluctuates, the sled motor 7 can be driven to rotate stably and accurately, and the sled control can be performed with high accuracy. Optical head body 3
1 can be moved.

As a result, tracking control can be reliably performed, and thus reproduction can be reliably performed.

When the optical head 3 (objective lens 32) is moved to a target position on the optical disk 2, that is, to a target track (target address), the level (voltage value) of the thread servo signal becomes a negative value. It may be.

In such a case, in order to be able to move the optical head main body 31 so that the objective lens 32 returns to the reference position, for example, the above-described threshold level (reference voltage value) is also set to the negative side. A pulse signal (pulse voltage) having a pattern corresponding to the moving direction of the optical head main body 31 is generated at the above-described predetermined timing, and the pulse voltage is applied to the sled motor 7.

The optical disk device of the present invention uses the above-described CD.
-Not limited to the ROM drive device, for example, a CD
Various types of optical disc devices for recording and reproducing recordable and reproducible optical discs (optical discs having pre-grooves), such as -R, CD-RW, DVD-R, DVD-RAM, and CDs
(Compact discs) and other read-only optical discs,
The present invention can be applied to various types of optical disk devices for reproducing a recordable / reproducible optical disk.

Further, the optical disk device of the present invention can be applied to various optical disk devices for recording and / or reproducing a plurality of types of optical disks.

According to the present invention, the drive of the sled motor can be performed in recording information on the optical disk in the same manner as in the above embodiment.

The optical disk device of the present invention has been described based on the illustrated embodiment. However, the present invention is not limited to this, and each component may have any configuration having the same function. Can be replaced by

For example, in the present invention, the pulse voltage may be applied to the sled motor by a logic circuit.

In the present invention, the pattern of the pulse voltage is not limited to the above embodiment. For example, even if the first pulse voltage 51 and the second pulse voltage 52 of the pulse voltage are discontinuous, Good.

In the present invention, the first pulse voltage 51
Is equal to the absolute value of the second pulse voltage 52, and the pulse width (application time) of the first pulse voltage 51 is
The pulse width (application time) of the second pulse voltage 52 may be larger (or longer).

In the present invention, the first pulse voltage 51
Is greater than the absolute value of the second pulse voltage 52, and the pulse width (application time) of the first pulse voltage 51 is
The pulse width (application time) of the second pulse voltage 52 may be larger (or longer).

In the present invention, the first pulse voltage 51
, The number of pulses of the second pulse voltage 52 may be one, and the number of pulses of the first pulse voltage 51 may be one, and the number of pulses of the second pulse voltage 52 may be plural. Further, the first pulse voltage 51 and the second pulse voltage 52 may each have a plurality of pulse numbers.

In the above embodiment, the sled servo signal (voltage), that is, the tracking actuator 4
Objective lens 32 based on a signal corresponding to the drive voltage
Is configured to detect the amount of deviation from the reference position, but in the present invention, for example, a tracking servo signal (voltage),
May be configured to detect the amount of deviation of the objective lens 32 from the reference position based on the drive voltage.

In the present invention, when the tracking servo signal (voltage), that is, the drive voltage of the tracking actuator 41 reaches the reference voltage value, the amount of deviation of the objective lens 32 from the reference position has reached the threshold value. May be configured.

[0110]

As described above, according to the optical disk device of the present invention, the behavior (drive) of the sled motor is stabilized, and in particular, the effects of hunting and cogging of the sled motor can be effectively prevented.

As a result, the accuracy of tracking is greatly improved, and recording and reproduction can be reliably performed.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment (main part) of an optical disk device of the present invention.

FIG. 2 is a plan view showing an embodiment (with a casing removed) of the optical disk device of the present invention.

FIG. 3 shows a thread servo signal (voltage) according to the present invention;
5 is a timing chart of a signal (voltage) from a comparator and a signal (voltage) from a pulse generation circuit.

FIG. 4 is a flowchart showing a control operation of a control unit at the time of thread control in the present invention.

FIG. 5 is a block diagram showing a conventional optical disk device.

FIG. 6 is a timing chart of a thread servo signal (voltage) of a conventional optical disc device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Optical disk apparatus 2 Optical disk 3 Optical head 31 Optical head main body 32 Objective lens 311 Support part 4 Actuator 41 Tracking actuator 42 Driver 5 Laser diode 51 Laser light 6 Split photodiode 7 Thread motor 71 Driver 8 Rotation axis 81 Lead screw 9 Control means 91 Pulse generation circuit 11 Spindle motor 12 Rotary shaft 13 Turntable 14 Reduction gear 141 Worm wheel 142 Pinion gear 15 Rack gear 16 Guide shaft 21 Tracking error signal generation circuit 22 Tracking servo circuit 23 Thread servo circuit 24 Comparator 24 51 First pulse voltage 52 Second pulse voltage 101 to 103 Step 210 Optical disk device 220 Tracking error signal generation Road 230 optical head 241 tracking actuator 242 driver 250 tracking servo circuit 260 the sled servo circuit 270 thread motor 271 driver

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Mamoru Takebayashi 1601 Sakai, Atsugi-shi, Kanagawa F-term in Atsugi Works, Mitsumi Electric Co., Ltd. 5D118 AA13 BA01 BF02 BF03 CA14 CA15 CD03

Claims (10)

[Claims] A rotating drive mechanism for mounting and rotating an optical disk; an objective lens; an optical head body; and an actuator for moving the objective lens relative to the optical head body in a radial direction of the optical disk, An optical head provided movably in a radial direction of the optical disc; and an optical head moving mechanism that includes a thread motor and moves the optical head in the radial direction of the optical disc by driving the thread motor. An optical disc apparatus for performing recording and / or reproduction, comprising: a shift amount detecting unit that detects a shift amount of the objective lens with respect to a reference position set on the optical head main body; When the deviation amount reaches a threshold value, a predetermined pattern of pulses is sent to the sled motor. By applying a pressure, an optical disc apparatus characterized by being configured to drive the sled motor. 2. The optical disk device according to claim 1, wherein the threshold value is smaller than a movement limit value of the actuator from the reference position. 3. The optical disk device according to claim 1, wherein the pulse voltage of the predetermined pattern includes a first pulse voltage and a second pulse voltage having different polarities. 4. The optical disk device according to claim 3, wherein the application of the first pulse voltage and the application of the second pulse voltage are performed continuously. 5. The absolute value of the second pulse voltage is less than the absolute value of the first pulse voltage.
An optical disk device according to claim 1. 6. The optical disk device according to claim 3, wherein an absolute value of the first pulse voltage is sufficiently larger than an absolute value of a voltage at which the sled motor operates. 7. The optical disc apparatus according to claim 1, wherein the displacement amount detection means detects the displacement amount based on a drive voltage of the actuator or a voltage corresponding thereto. 8. The optical disk device according to claim 7, wherein the shift amount reaches the threshold when the drive voltage of the actuator or a voltage corresponding thereto reaches a reference voltage value. . 9. When driving the actuator to cause the objective lens to follow a predetermined track of the optical disk, the optical head body is moved by driving the thread motor, whereby the objective lens is moved to the reference position. 9. The optical disk device according to claim 1, wherein the optical disk device is configured to return to step (c). 10. The optical disk device according to claim 1, wherein the thread motor is a DC motor.